Set-up for explosive forming



y 7, 1970 R. v. PIKHTOVNIKOV ET AL SET-UP FOR EXPLOSIVE FORMING FiledApril 4 1968 OODOOGOOOOOOODOOO Unlted States Patent 01 3,518,860 SET-UPFOR EXPLOSIVE FORMING Rostislav Vyacheslavovich Pikhtovnikov, ProspektLenina 3, kv. 227; Alexei Alexeevich Gubsky, Ulitsa Ekonomicheskaya 7,kv. 19; Vladimir Karpovich Borisevich, Zhildon Khai 1, kv. 17; LidiaRostislavovna Kiriclienko, Prospekt Pravdy 7, kv. 227; Albert PetrovichBarsukov, DMS, kv. 4; Arkady Fedorovich Plisko- Vinogradsky, UlitsaFrunze 15, kv. 9; Vladimir Ivanovich Shalygin, Zhildon Khai 1, kv. 31;and Georgy Arkadievich Repin, Ulitsa Summskaya 45, kv. 11, all ofKharkov, U.S.S.R.; Anatoly Anatolievich Buzukov, Morskoi prospekt 36,kv. 28, Novosibirsk, U.S.S.R.; and Leonid Vsevolodovich Litovsky, U]. 23Avgusta 33, kv. 66; and Valery lvanovich Eliseev, DMS, kv. 53, both ofKharkov, U.S.S.R.

Filed Apr. 4, 1968, Ser. No. 718,700 Int. Cl. B21d 26/08 US. CI. 72-56 2Claims ABSTRACT OF THE DISCLOSURE An apparatus for the explosive formingof sheet material. The sheet material is placed on a die within achamber provided with a header surrounding the die. Fluid is sprayed outof the header to form a domed curtain over the die and workpiece. Thespray constitutes the medium that transmits the explosive energy to theblank.

This invention relates to forming equipment wherein no presses are used,namely to explosive forming equipment.

Most successful and effective use of the invention can be expected inthe production of large-size articles (for example, articles with crosssections of over 2 m.).

Explosive forming set-ups are well known. In these setups fluid mediumwhich fills a vessel, transfers to the blank fixed in a die theexplosion energy of a charge fixed in the vessel by some arrangement.The vessel can be of two types: stationary or single-use type.

The stationary vessel is a reinforced concrete basin with a metallining. The die with the blank and the arrangement to fix the charge arelocated within the basin filled with fluid medium.

A disadvantage of stationary basins lies in a great labour consumptionand cost to build the basin itself. In the process of operation thebasin walls are eventually destroyed by shock Waves in the fluid mediumresulting from the charge explosion.

Single-use vessels are made of cheap materials (say, cardboard, veneer).These vessels are placed on the die with the fixed blank, prior to theexplosion. The charge fixture is mounted inside the single-use vessel.

Employment of single-use vessels is limited by the article overalldimensions (to be not more than 2 111.). Charge explosion in asingle-use vessel causes a strong air blast wave and fluid mediumsplashing. Auxiliary time to mount the single-use vessel increases theforming cycle time.

The object of the present invention is to provide an explosive formingset-up that would be of simpler design as compared to the prior-artinstallations of this type and would have greater productionpotentialities.

Another object of the present invention is to design an explosiveforming set-up that would be reliable in operation and convenient inservice.

And still another important object of this invention is to design aset-up that would be cheap to make.

In compliance with the afore-mentioned and other objects of theinvention the device for fluid medium in ice the proposed set-upconstitutes, according to the invention, at least one header surroundingthe die and having jets to spray the fluid medium so as to create overthe die and the charge fixture a domed curtain whose dropping streamsform the medium that transmits explosion energy to the blank.

In case the proposed set up is employed inside a closed building, it isadvisable to locate the charge fixture and the die with the 'header in aburied armoured vessel. The best solution will in this case 'beaccomplished by employing, in the top part of said vessel, an additionalheader with jets spraying fluid medium in order to form a curtainpreventing fountains of fluid medium to be thrown out of the vessel atthe moment of explosion.

Such a design of the suggested explosive forming setup makes it cheap toconstruct, reliable in operation, convenient in service and promisinggreat production potentialities.

Besides, the production cycle time is sharply cut down due to decreasedauxiliary time.

The invention is further explained by a detailed description of apreferred exemplary embodiment thereof with reference to an appendeddrawing, wherein:

FIG. 1 is a longitudinal section of the set-up of the invention.

The explosive forming set-up has a buried armoured vessel-pit 1, whereinanvil 2 mounts die 3 to locate and fix blank 4. In the set-up there areprovided arrangement 5 to fix charge 6 and a device for fluid mediumtransmitting explosion energy to blank 4. According to the inventionthis device comprises header 7 surrounding die 3 and having jets 8 tospray fluid mediumwater, which forms a domed curtain 9 over die 3 andarrangement 5 that fixes charge 6. The dropping water streams 10 ofcurtain 9 are the medium that transfers explosion energy to blank 4.

When the explosive forming set-up is located inside a closed building,it is advisable to mount, in the pit top part, at least one additionalheader 11 for fluid medium, with jets 8 to form curtain 12 in order toprevent fountains of fluid medium to spring up from pit 1 at the momentof explosion.

The number of headers 7 and 11 is chosen according to the value ofcharge 6. The greater the charge value the more the amount of fluidmedium (water) to be atomized in the curtains.

The proposed set-up carries out explosive forming in the following way.

Blank 4 is placed on die 3 and fixed by hold-down ring 13. Charge 6 isfixed by means of arrangement 5 at a calculated distance from blank 4.Then water (fluid medium) is pressurized by a pump (not shown in FIG. 1)into header 7 and sprayed through pulverizers 8. In a period of '34seconds after the pump has been started, a stable domed curtain 9 isformed over die 3 and the charge fixing arrangement 5, the droppingstreams 10 of said curtain being directed at the blank center.

At that moment charge 6 is remotely initiated.

Simultaneously with header 7 water is fed to header 11 whose jets spraywater forming curtain 12 which prevents water fountains to spring upfrom pit 1 at the moment of blast.

Explosion energy of charge 6 is transmitted by the dropping waterstreams 10 to blank 4 thus deforming it.

In a period of 23 seconds after the blast, water feed to headers 7 and11 is stopped whereupon the finished product is removed from the die.

Employment of the device for fluid medium in explosive forming plants,said device comprising at least one header 7 surrounding die 3 andhaving jets 8 which spray fluid medium to form a domed curtain 9 overdie 3 and 3 arrangement 5 thatfixes charge 6, permits also to obtain ahigh useful efficiency of explosion energy for blank deformation, aswell as to reduce the unfavourable effects of explosions on thepersonnel and surrounding structures.

The domed curtain 9 of atomized fiuid medium to a considerable extent(up to 90%) absorbs the energy of the shock wave produced by theexplosion of charge 6.

Fluid medium is fed through header 7 and jets 8 within a short period oftime, which sharply increases labour efficiency due to a decreasedduration of auxiliary operations. Besides, fluid medium consumption ratedrops substantially.

The proposed set-up permits a short-time assembly, using standard units,of a header of required size according to the overall dimensions of thearticle.

What we claim is:

1. A set-up for explosive forming comprising: a die to locate and fixthe blank; an arrangement to fix the charge; a device for fluid mediumtransmitting explosive energy to the blank, said device including atleast one header surrounding said die and having jets to spray fluidmedium which forms a domed curtain over said die with the blank and saidcharge fixing arrangement, the dropping streams of said curtainconstituting the medium that transmits explosion energy to said blank.

2. A set-up as claimed in claim 1, in which said die with a header and acharge fixing arrangement are located within an armoured vessel in Whosetop part at least one additional header with jets is mounted to sprayfluid medium in order to create a curtain preventing a fountain of fluidmedium from being thrown 01f from said vessel at the moment ofexplosion.

References Cited UNITED STATES PATENTS 3,214,950 11/1965 Nemitz 7256RICHARD J. HERBST, Primary Examiner

